Panel board



May 2, 1939. -w. P. McwHoRTER PANEL BOARD Filed Aug. 24, 1956 3 Sheets-Sheet 1 May 2, 1939. w. P. MowHoRTER 2,156,479

PANEL BOARD Filed Aug. 24, 1936 .'5 Sheets--Sheeakl 2 am /Q www 3&3 Camzwoyd, @MHP/m May 2, 1939- W. P. MCWHORTER 2,156,479

PANEL BOARD Filed Aug. 24, 1956 3 Sheets-Sheet 3 Patented May 2, 1939 UNITED STATES PATENT OFFICE 20 Claims.

This invention relates to panel board systems and more particularly to panel board assemblies of the type used for connecting and fusing the electrical distribution circuits of a building to the service mains.

Heretofore, when a contractor has undertaken to provide the electrical distribution system for any particular building and has decided upon the type and size of panel board needed to fulill the requirements of that system, it has usually been necessary to have the board made up specially by some panel board manufacturer. This procedure is not only costly but also tends to delay completion of the building. For the manufacturer or the wholesale distributor to carry in stpck a suiiicient number of different panel board arrangements to meet the daily demands of the trade would require a stock of such size as to be prohibitive from the standpoints of both storage space and investment. Consequently, in most cases the electrical contractor has had to place a special order for his panel board equipment and to patiently await construction and delivery by the manufacturer before completing his work.Y

It is therefore one of the objects of the present invention to provide a panel board system of component elements of novel construction which may be manufactured and stocked in quantityand assembled in numerous different combinations so as to produce any desired arrangement of circuit connections, switches and fuses.

Another object is to provide a panel board system comprising a housing unit, molded terminal block, base block, plug fuse and cartridge fuse units, and conductor and switch elements, all oi which are of novel construction and especially adapted to cooperate with one another in the building up of panel board assemblies of varying sizes and circuit arrangements.

A further object is to provide a plurality of units or elements of distinctive construction which may be manufactured and stocked as standard panel board parts and combined with one another in many different arrangements to produce panel board assemblies of various designs.

Still another object is to provide a panel board section or branch circuit unit of new and iinproved construction the component parts of which may be separately manufactured in an economical manner and readily assembled with a minimum of effort.

A still further object is to provide a panel board section of the built-up type in which fuses of the plug and cartridge types may be used interchangeably and wherein either single, double or even triple pole switches, or various combinations thereof, may be employed.

Another object is to provide a base block unit for panel boards of novel form which may be molded in one piece of non-conducting material and on which may be mounted the various elements of the fuse and switch units and the current conductor elements without requiring any machining or drilling after removal of the unit from the mold.

Another object is to provide a pair of fuse units of new and improved construction, one adapted to receive plug fuses and the other cartridge fuses. which are interchangeably mountable in a panel board section, the cartridge fuse unit also einbodying a novel form of hinged cover which serves to insert the fuses in and withdraw them from the fuse clips without the necessity for actually taking hold of the fuses with the fingers.

Another object is to provide an improved housing or cabinet u nit for panel board assemblies which is so constructed that the elements of the assembly may be properly mounted therein without the use of screws or other fastening means.

Another object is to provide a novel form of switch especially adapted for mounting without the use of tools in the base block unit oi' the present invention, the elements of which switch are so constructed as to be capable of providing either a single, double or triple pole switch as desired.

Another object is to provide new and improved means for supporting the bus bars of a panel board assembly and for connecting the service wires and the branch distributing circuits thereto.

These and other objects will appear more fully upon a consideration of the detailed description oi the embodiment of the invention which follows. Although only one particular panel board assembly is described and illustrated in the accompanying drawings, it is to be expressly understood that these drawings are for the purpose of illustration only and are not to be construed as defining the scope of the invention, reference being had for this latter purpose to the appended claims.

Referring now to the drawings, wherein like 45.

reference characters indicate like parts throughout the several views:

Fig. 1 is a `front elevation of a panel board assembly embodying the present invention with the front trim removed, there being only one panel board section or branch circuit unit shown in place although two cabinet or housing units are shown to illustrate the manner in which a panel board of any desired size may be built up from the units constituting the system oi the present inten@ tion;

Fig. 2 is a vertical section taken substantially on line 2 2 oi Fig. l but with the iront trim shown in place;

Fig. 3 is a iragmentary'perspective view oi one corner oi the upper vend oi the assembly oi Fig. l with the cabinet top cover removed from the body thereof so as to illustrate the construction and manner of assembly of said elements;

Fig. 4 is a horizontal section taken substantially on line 4-'4 of Fig. 1 but with the iront trim shown in place;

Fig. 5 is a horizontal section takensubstantially on line 5-5 of Fig. l showing the panel board section or branch circuit unit .in plan;

Fig. 6 is a horizontal section through the panel board section taken substantially on line @-5 of Fig. 1;

Fig. is a rear elevation of the panel board sec tion and terminal bloei: unit of the assembly shown in Fig. 1 illustrating the interior construction of the panel board section Fig. 8 is a iront elevation ci the integrally molded base block unit oi the panel board section with all of the fuse, switch, conductor and other detachable elements removed;

Fig. 9 is a horizontal section through the base block unit taken substantially on line of 30 Fis. 8:1-

Figs. 10, 11 and 12 are vertical sections transversely of the panel board section taken substantially on lines IG-Iil, li--il and l2|2, respectively, of Fig. 5;

Fig. 13 is an exploded perspective view of the novel form of switch constituting a part of the present invention which is shown in assembled condition in Figs. 5, 6, 'l and l0;

Fig. 14 is an exploded perspective view of the cartridge fuse unit of the present invention; and

Fig. 15 is a perspective view of the inner surface of the cover of the cartridge fuse unit of Fig. 14 illustrating the manner in which the fuses are carried and. properly positioned thereby.

Referring first to Fig. 1, there is shown therein a panel board assembly of the type used for connecting and fusing the electrical distribution circuits oi a building to the service mains which is kbuilt up in a novel manner of a number of com ponent elements of new and improved structure especially adapted to cooperate with one another in the construction of panel board assemblies oi any desired size and arrangement oi circuit connections, switches and fuses. As illustrated, the assembly comprises as its principal elements one or more housing or cabinet units iii in which are removably mounted at least one terminal blcch unit 22, two pairs of bus bars 23 and as many panel vboard sections or branch circuit units 2G as may be required to fuse and switch the circuits of the installation in question. Each of the panel board sections 24 is in turn built up of a number oi individual elements including a molded base block unit 26, a pair of interchangeable fuse units 2B andZ'l which, in the embodiment illustrated, are shown as plug and cartridge fuse units, respectively, and a plurality oi switch units of which only the operating levers and handles are visible in Fig. 1. As will be apparent irorn the detailed description which follows, each of these various units and elements of the panel board system of the present invention is so constructed that the entire assembly may be put together and mounted in place quickly and easily and with a minimum use ci tools. v

aisance As shown best in Figs. l-d, each ci the housing or cabinet units ti comprises a body member having a dat rear wall 2@ and a pair of side walls 2@ extending forwardly therefrom, a top cover El@ and a bottom cover iii, all preferably made ci sheet metal. The body members are so ccnstructed, however, that two or more of them may be connected together to form a cabinet of any desired size, in which event it will be understood that only one top cover 3c and one bottom cover 3l are required for the entire cabinet.

In the rear wall 28 of the body member adjacent the tcp thereof there are provided a pair 'of hanging openings 32, preferably circular at their bottom ends but narrowed at their upper ends as illustrated, which are adapted to receive the enlarged heads and Shanks of suitably formed studs or lugs 33 which may be embedded in or otherwise secured to the wall upon which the panel board assembly is to be mounted. Each o! side walls 29 is provided with an inwardly turned flange 34 on which the usual form oi removable iront trim 35 is adapted to rest. As shown in Fig. 4, the trim 3b is provided with a suitable door :it of substantially the same width as the long dimension of the panel board sections 2d and a pair of rearwardly extending flanges 3l the rear edges of which are adapted to engage in suitable grooves 3e formed in the top or outer surface of each base bloei; unit 25 closely adjacent the ends thereof so as to form a pair of wiring troughs or gutters 39 extending the full height of the cabinet and in which the branch circuit wires are housed.

The top end of the body member oi the cabinet unit and the top cover therefor are provided with cooperating means of novel character whereby the cover and body member may be detachably secured together in assembled relation in an extremely simple and easy manner. As best illustrated in Fig 3, the upper end of the body member is provided with a sheet metal skirt it which is secured to the rear and side walls of the body member in any suitable manner as by rivets Gi and extends above the topv edges thereof for a distance slightly less than the depth of the flange il! of top cover 30. Each oi' the forward edges of the skirt 40 is provided with a rearwardly ex- -tending slot 43 which is adapted to receive the shank of an enlarged headed pin Mi secured to and extending laterally outwardly from the ange i3 of top cover 3B. The rear wall ci the skirt til is then provided with a pair of cut-out tonguesA which are initially bent downwardly to a forwardly extending position so as to pass through corresponding openings 46 formed in the rear wall of flange 42. With this construction, top cover 3U may be assembled with the body member of the cabinet unit by rsimply sliding it rearwardly in a horizontal plane in such a manner that the tongues 35 pass through openings it and pins N are received in slots d3. When thus aembled, the top cover 30 may be locked in place by simply flattening the tongues d5 to vertical positions as indicated in Figs. l and 2.

The means by which the bottom cover 3l is detachably connected to the bottom' end of the cabinet unit 2| comprise the same elements as those just described in connection with the top cover, but the elements are reversed in so far as the members by which they are carried are concerned; that is, the skirt member til' with its slots 43 and tongues 45 is secured to the bottom cover 3l instead of to the cabinet body member, while the pins 44 and openings 46' are mounted on and formed in the bottom end of the body member rather than the cover. By thus making the elements of the connecting means at the top of each cabinet unit complementary to those at the bottom end thereof, it is possible to connect together two or more of said units in the manner indicated in Fig. 1 to form a housing or cabinet of any desired size.

' ilar knock-out portions.

general configuration of a Z-bar.

In order to avoid the necessity for using screws, bolts, or other fastening means for mounting the terminal block and branch circuit units in the cabinet, the latter is provided with novel means for supporting and holding these units in place which require no tools for manipulation and which, when the panel board is completely assembled, are rendered inaccessible, and hence p-rotected against unauthorized or accidental displacement, by the flanges I1 of trim 85. As shown, the body member of each cabinet unit 2| has fixedly secured to its rear wall 25 adjacent one side thereof and extending the entire height thereof a retaining member 55 having the 'Ihe rear or bottom flange 58 of this retaining member 55 is suitably secured to rear wall 28 as by rivets 51 and the web 58 thereof projects forwardly a distance slightly greater than the thickness of the base 58 of the terminal block unit 22 and of the shoulder 88 which is formed integrally with and projects outwardly from each end of the base block unit 25 of the panel board section 24. 'Ihe web 58 terminates in an inwardly directed flange 5I which is adapted to engage the outer surfaces of base 59 of the terminal block unit and shoulder 88 of the panel board 'section and to hold said units against the rear wall 28 of the cabinet.

The cabinet unit also carries adjacent the other side of rear wall 28 a second retaining member 82 of substantially the same construction as member 55, except that the member 82 mais capable of a limited movement relative to rear wall 28 toward and away from member 55. In the embodiment illustrated, the rear or bottom flange 63 of retaining member 82 is provided with a pair of diagonally extending slots 84 in which are engaged the Shanks of enlarged headed pins 85 which are secured to and project outwardly from rear wall 28. Slots 8l are so slanted that their upper ends are further away from retaining member 55 than their lower ends, the result being that retaining member 82 tends'normally under the influence of gravity to remain in its closest position to retaining member 55; when in this position, the webs 58 and 86 of the two retaining members are spaced apart by a distance approximately equal to the long dimensions of each of the terminal block units and panel board sections. Pins 65 and slots 54 are also so located that when retaining member 82 is in its downward position, in which its inwardly directed flange 81 will engage and retain the end of thebase 58 of the terminal block unit and the shoulder 80 on the end of base block unit 25, the upper end of said retaining member is flush with the top edge of rear wall 28 of the cabinet body member.

In addition to retaining members 55 and 82 which hold the terminal block and branch circuit units in place against the rear wall 28 of the cabinet, means are also provided for positively limiting Vthe position of the lowermost branch circuit unit in the cabinet and thereby supporting the same and all other units which lie thereabove. In the embodiment shown, the rear wall 28 of the cabinet body member has secured thereto at the proper distance from its bottom edge and inside of retaining members 55 and 82 a pair of supporting or stop members 88 of substantially L-shape, one arm 88 of each of said members beingriveted to rear wall 28 and the other arm 10 extending forwardly or outwardly therefrom in suitable position to form a support or rest for the lowermost panel board section of the assembly. In this connection, it should be noted that the height of the rear wall 28 of each cabinet body member is preferably approximately equal to four times the width of a single panel board section, and that supporting members 88 are so positioned that the upper edges of their forwardly extending arms 10 are spaced above the bottom edge of rear wall 28 by a distance also equal to the width of one panel board section. With these proportions, it is possible to mount two panel board sections and a terminal block unit in a single cabinet unit and still leave the required wiring space on all sides of the assembly. When the panel board assembly requires more than two branch circuit units, two or more cabinet body members are connected together in the manner indicated in Fig. l, and the forwardly projecting arms 1i) of supporting members 58 of all body members but the lowermost ones are either removed or flattened down out of the way so as to not interfere with the installation of the branch circuit units. Alternatively, all of supporting members 88 may be left in their original positions so as to provide spaces equal in Width at least to the width of one branch circuit unit between the groups of units supported in each of the connected cabinet body members.

' Referring now to the means for supporting the bus bars 28, it will be seen from Figs. 1, 2 and 7 that the upper end of each of the bus bars is supported on, and passes through a suitable positioning groove 1| formed in the lower edge of, the terminal block unit 22 which is formed of a non-conducting material, while the lower ends of said bars are maintained in insulated relatiopship with respect to the rear wall 28 of the cabinet body member by resting upon a pair of blocks 12, also made of a non-conducting material. As shown best in Figs. 5. 6 and 7, each of blocks 12 extends upwardly beneath the lower side wall of the lowermost panel board section and is provided with a horizontally extending groove 13 in the outer surface thereof in which the side wall of the panel board section is adapted to t, thereby forming a supporting connection between said section and said block The portion of terminal block unit 22 immediately underlying the ends of bus bars 23 is holl'owed out or recessed to provide a suitable trough 14 to accommodate the clamps by which the service feed Wires 48 and 50 are electrically connected to the bus bars 23. Although the clamps may be of any desired construction, where two bus bars are to be fed in parallel from the same main the clamp may be of the form illustrated at the left in Fig. l and comprise a substantially rectangular strap 15 having slots in the opposite walls thereof adjacent the ends to receive the bus the bus bars and wires and U-shaped clampingr members 'IG interposed between the ends or the strap and bars and urged toward the latter by screwsll'i which are threaded into the ends ci the strap. As shown, the feed wire it? to be connected to the bus bars is held against one of them by the U-shaped clamping member "lli, the current mso passing from the wire through the strap lli and the other clamping member lo to the other bus bar. if separate clamps are desired for each bus bar, it is obvious that. by simply eliminating the central portions of the side walls of clamp lo, individual clamps 'it' may be formed, as illustrated at the right in Fig. l. Such clamps would be used, :lor instance, where it is desired that the cartrldse'fused branch circuits 5t and 5ft should carry a potential twice that of the plus fused circuits iii and in such a'circuit arrangement, a Sumner 'wire itt may be provided to connect one end oi double clamp 'lli with one or individual clamps l5', the other clamp iii receiving7 wire Just above the trough. lll, the terminal bloote unit 22 is provided with @smelly extending barrier 'i8 having slots l@ therein to aoconirno date the feed mains, said barrier insulating the connections to the bus bars from the terminal strip 80 by means oi which the return wires oi the branch circuits are connected to the third Wire or neutral service main t9, the latter being connected to terminal strip t@ by any suitable form of connector ti.

'I'he panel board section or branch circuit unit of the present invention is itself of extremely simple and novel construction and is especially adapted, not only to receive fuse units of the plus and cartridge type interchangeably. but also to be assembled with a minimum use oi' tools. As shown, the base bloclr. unit 2b upon which all of the other elements of the section are removably mounted is so designed as to be capable of molding lin one piece from any suitable nonconducting material, such as Bakelite. venience in describing this unit, the surface or wall thereof through which the switch operating elements extend will be referred to as the top of the unit, although when the latter is mounted in its proper position in the panel board cabinet this wall is actually in a vertical plane lacing,1 the door of the cabinet. A

As best illustrated in Figs. 5-12, each base block unit 2li comprises a pair of parallel. elongated side walls i2 connectedat their ends by end walls at and a top wall which connects the central portions oi the top edges or side walls 82 but terminates short oi the ends ci said walls so as to form a pair o identical recesses l5 and @t at the ends oi the base blocls unit in which the fuse units are adapted to be removably housed. The bottoms o recesses @il and il@ are formed by supporting platforms el and til, re=J spectively, which connect the side walls b2 at points intermediate the top and. bottom edges thereof. Extending lengthwise ci the unit between the supporting platiorms'tll and 8i! are a pair of parallel partition walls 8S and @t which are integral with top wall Srl at their upper edges and have their lower edges substantially coplanar with. the bottom surfaces of platforms fil and Btl, except for a pair of substantially semicircular extensions 9i on each, which extend toward the open bottom of the unit. The function of the extensions 9i will be described later in connection with the description of the' 'switch elements which are adapted to be removably mounted in For con- I ateatro the channels t2, 83 and 98 formed between partltion walls @il and Slt] and side walls S32.

As the bese block unit 2li comes from the mold, there is no machining, drillingr or other wort; to be done thereon in order to nt it for reception of the various fuse, switch and conductor elements other than the removal from the top wall et of whichever oi sin knock-out portions @Si it is de-l aired to remove to accommodate the operating elements of the switches. As sharm in the drawings, the middle knock-out portion to of each set of three is removed. All other openings, slots and recesses in the walls and platforms of the base block unit shown in the drawings are provided during tle molding operation, it being understood that those which do not serve to receive any of the 'removable elements of the assembly are either necessary or preferable in order to facilitate the molding of the entire unit with as simple a mold as possible.

Although, as previously poind out, the recesses fili and @t are adapted to receive fuse units o either the plus or cartridge type interchangeably, the embodiment of the invention illustrated includes a plus fuse unit 2li in recess B5 and a cartridge fuse unit 2l in recess St, both units being oi novel construction such that they may be inter-changed one -ior the other. As shown best in Figs.4 o and ll, the plus fuse unit 28 comprises a body member t@ molded in one piece of non-conducting material having a pair of recesses lil formed in the upper surface thereof in 'which are removably housed'iuse receptacles t8 of known type, the contact bolts Q9 of said receptacles passing through holes molded in body lmember et into the bottom oi' recess 85 just above the upper surface of platform di. Removably secured to the bottom of body member 98 by bolts t@ and nuts itil are a pair of connector strips lill which are also threaded to receive the ends of tap bolts or screws m2 which extend upwardly through holes its formed in platform 8l.

-V Secured beneath the heads oi bolts I 02 and in electrical contact through said bolts and conhector strips iii with contact bolts 99 are a pair of conductor members ltd which may be stamped out of relatively thin metal and bent to the shape indicated in the drawings, each oi said members lying adjacent one oi sidewalls 32, extending toward the central portion of the branch circuit unit and terminating in a downwardly turned switch jaw i935. Complementary switch jaws |96, also lying in channels Q2 and til but spaced from jaimito, are formed on the ends of conductor members itl, the latter beiner so shaped as to rit over partition walls il@ and @il and to extend outwardly toward the end of the unit beneath platform t? to positions underlying holes it@ which are molded in said platform to receive bolts tot?. The threaded. ends of bolts it not only pass through the ends of conductor members itl but also extend through the bases of a pair of substantially U-shaped bus bar clips il The clips llt, conductor members lill and bolts itil are held in assembled relation and secured to the platform. t? by ,suitable nuts I I I. Each of conductor members lili and lill is provided with a lip portion like that indicated at HZ in Fig. 6 which is adapted to engage the upper surface of platform ill and thereby lock said member against downward movement under the action of the switch elements later to be described. The bus bar clips lill thussecured to the under side of platform 81 are spaced from one another as shown and aligned with slots ||3 molded in the lower edges-of side walls 82 through which the bus bars 23 are adapted to pass transversely of the panel board section. In order to facilitate assembly and proper positioning of the bus bar clips and conductor members, the under surface of platform 81 is preferably provided with irregularly shaped. downwardly projecting portions ||4 and ||5 which define the desired locations of said elements.

When the plug fuse unit just described is placed ln recess 85, it rests on supporting platform 81 by means of a pair of legs ||6 formed integrally with body member 86 adjacent one end thereof and a pair of shoulders ||1 formed adjacent the other end of said vbody member which engage and rest on raised extensions ||8 of platform 81. The conductor members |01 are then placed in their proper positions and the bolts |02 passed through holes |03 and threaded into connector strips |0|, thereby securing the fuse unit to the platform 81. The bus bar clips and their associated conductor members |01 are, of course, assembled prior to the mounting of the fuse unit in recess 85. .When the elements are thus assembled, it is obvious that a combined frictional and electrical connection with the bus bars 23 may be made by simply forcing the panel board section inwardly over the bus bars, permitting the latter to enter slots ||3, until the section comes into contact with rear wall 28 of the cabinet and rests thereagainst at its ends, it being noted that the bottom edges of the side walls 82 of the base block unit 25 intermediate the ends thereof terminate a short distance above said rear wall. With this construction, a pair of current conducting paths are provided with the bus bars 23 through their associated clips ||0 and conductor members |01 to switch jaws |06 whence the current may flow, upon the closing of the circuits to the complementary switch jaws |05, through conductor'members |04, bolts |02, connector strips |0| and contact bolts 99 to the plug fuses ||3 which are adapted to be screwed 'into receptacles 88 in the usual manner. 'I'he circuits continue from fuses ||9 through feeder straps |20 which extend outwardly from the fuse unit 26 through openings |2| formed in the end wall 83 of base block unit 25, the outer ends ci said feeder straps |20 being adapted to have connected thereto the branch circuit wires and 52.

The cartridge fuse unit 21 which is shown housed in recess 86 is of the same external dimensions as plug fuse unit 26 so as to be interchangeable therewith, and is also adapted to take care of two branch circuits which may be fed from the other pair of bus bars 23. construction of the cartridge fuse unit is best illustrated in Figs. 6, 12, 14 and 15, and comprises, in addition to two pairs of fuse clips |22 and |23, three separately moldable elements of non-conducting material which may be readily assembled together without the aid of any tools whatsoever-that is, a base block |24, a cover member |25, and a hinge-forming member |25 which is adapted to hold the cover to the base block in hinged relationship.

As shown, the 'bottom Wall |21 of base block |24 s provided with a downwardly projecting portion |28 which extends transversely across the central portion thereof and a plurality of legs |28 projecting from the inner end wall |30 o1 said block by means of which the fuse unit is supported on platform 88 with the metallic elements of said unit out of contact with the bolts 'under surface of said platform 83.

The

|08' which secure the bus bar clips H0' to the The upper surface of bottom wall |21 of the base block |24 is provided with two pairs of suitably shaped recesses |3| and |32 in which the fuse clips |22 and |23, respectively, are adapted to be seated and held against turning out of their proper positions. Recesses |3| are provided with holes |33 extending through bottom wall |21 in alignment with the holes |03' formed in supporting platform 88 through which pass the bolts |02 holding the conductor members |04' and their associated switch jaws |05' in secured position beneath platform 88. It will be noted that the bolts |02' of the cartridge fuse unit are longer than the corresponding bolts |02 of the plug fuse unit and that they pass downwardly through fuse clips |22, holes |33 and holes |03', having lock nuts |34 which thread up against the lower surface of bottom wall |21 of base block |24 as well as nuts |35 which secure the conductor members |04' thereto. Fuse clips |23 are fixed in their recesses |82 by bolts |36 which not only extend upwardly both through holes |31 formed in said recesses and through the fuse clips themselves but are also threaded into the inner ends of a pair of feeder straps |38 which extend outwardly through suitable openings |39 formed in the outer end wall |40 of base block |24 and are connected to branch circuit wires 53 and 54.

The cover member |25 of cartridge fuse unit 21 is adapted to be hingedly associated with base block |24 and to serve both as a cover for the unit and as a carrier for the cartridge fuses |4| which are mounted therein. As best illustrated in Figs. 14 and 15, there is formed integrally with the under side of the cover member |25 a downwardly projecting, transversely extending carrier member |42 in which are formed a pair of parallel, separated fuse receiving openings |43, said openings being coaxial with the fuse receiving portions of each pair of fuse clips |22 and |23 when the cover is in its closed assembled position. The central portion of fuse carrier member |42 is recessed as indicated at |44 so as to clear the barrier webs |45 and |46 which extend lengthwise of base block |24 between the two sets of i fuse clips.

The outer end of cover member |25 has formed integrally therewith a pintle member |41 which is adapted to be received inv a half round bearing groove |48 formed in the upper surface of the outer end wall |40 of base block |24. The adjacent edge of cover member |25 intermediate the ends of pintle member |41 is cut away as indicated at |49 to provide an opening in which may be received the hook-like upper end |50 of hinge-forming member |26 which thereby engages the upper surface of the pintle member |41 to complete the bearing therefor and to hold the same in the half round bearing groove |48. The intermediate or body portion of hinge-forming member |26 extends downwardly in contact With the outer end wall |40 of base block |24 to a position below the bottom wall |21 and is provided at its lower end with an inwardly extending projection |5| which engages the under surface of said bottom wall and locks the cover member |25 in hinged relationship with base block |24 when the unit is assembled, movement of the projection |5| out of locking engagement with the bottom of the base block being prevented by reason of the fact that, when the fuse unit is placed in the recess 86 of the base block unit of the panel board section, the intermediate or body portion of hinge-forming member |26 lies practically in contact with the inner surface of the end wall 83, as indicated in Fig. 6.

To facilitate the opening of cover member |25, the outer surface of the latter is preferably provided with a suitable recess |52 in which is housed a pull ring |53 of substantially U-shape, the ends of the ring being turned outwardly and engaging in openings ld extending through cover member |25. It will be understood that the ends of the pull ring |53 are inserted in openI ings E56 by nrst pressing them toward one another and then permitting the resiliency of the ring to expand them into said openings.

The cover member |25 may also beI provided on its under surface with a pair oi abutment members it@ against which the ends of the fuses tdi are adapted to rest as sliownyin Figs. 6 and i5, said abutments being" so located that when the fuses are in engagement therewith they are properly positioned with respect to the fuse clips. Since these abutment members are at the ends oi the fuses remote from the hinged edge ci cover member 82S, it will be seen that when the cover is being closed the pressure exerted. by fuse clips 23, which are the rst to be engaged by the fuses, forces the latter firmly' against abutment members ib and thereby assures proper positioning oi the fuses with respect to the fuse clips when the cover is completely closed. @n the other hand, when the cover is opened, the fuses are released hrst from fuse clips i2?. and -then from fuse clips i253, an ,action which results in pulling the ends oi the fuses free from abutment members idd and leaving them in readily removable position when the cover is completely opened.

As has already been indicated, the arrangenient oi bus ber clips, conductor and switch jaw.

members by which the current is delivered `from thebus bars to the branch circuits 53 and with which the cartridge fuses it! are associated is identical with that previously described in connection with the plug fuse unit 26. Conseouently, it is obvious that the two kinds of fuse units are interchangeable one with the other so as to make possible any desired fuse arrangement in each panel board section.

in order to control the opening and closing oi the fused circuits of the panel board section.

above described, there has been provided a novel form of snap acting switch which, while capable oi use in other surroundings, is especially l adapted for mounting without the use of took;

in the base block Vunit of the present invention. Although the elements of this switch unit are so constructed as to' provide either a single double or triple pole switch, as desired, the embodiment illustrated is adapted to serve as a double pole switch for opening and closing the two fused branch circuits at either end of the panel board section of the present invention.

As shown best in Fig. in, the switch unit comprises a pair of parallel, elongated bearing members |56 having aligned bearing studs tbl projecting inwardly therefrom on which is pivotally mounted a switch arm. its consisting of a pair of parallel side pieces G59 each having at one edge an inwardly turned flange |68, said flanges being connected together at one end of the arm |58 by a web tl at a point near to, but spaced from, the other end of the arm by a-second web |62, the pivotal axis of said arm being located intermediate said webs. The bearing members |58 are also provided with aligned openings |63 |62 oi switch aim it and is adapted to have detachablv connected to its end one end of a spring its the other end of which is similarly detachably connectable to web it. thereby resiliently connecting switch arm idd and switch lever ld..

it the end of switch arm it@ opposite that to which the spring il@ is connected, the side pieces it@ and. flanges it@ are cut in such a way as to form a pair ci tongues lli which, before assembly oi the .sv/itch, are bent outwardly as indicated in i3. The switch assembly is completed by a switch bar il@ molded in one piece oi non-conducting material which is adapted to be mounted on the last mentioned end of switch arm 58 by means ci a substantially T shaped lug llt formed integrally therewith. This lug il@ is so constructed es to slide into the space between the side pieces tot of the switch arm;

with the inwardly turned flanges it@ engaging the under .surface oi the heed of the T, and come to rest against the connecting web E62. The tongues iii may then be pressed inwardly toward one another into a groove iid formed in the outer edge face of switch bar H2 as indicated in Fig. 7, in which position said tongues prevent the switch bar from moving outwardly out oi its proper assembled relationship with the switch arm its. Switch bar il@ also has formed integrally therewith three spaced, outwardly projecting stub members tlc to each of which may be removably secured, as by a split cotter pin lib, a switch contact member ill suitably shaped to irictionally engage between and close the circuit across a. switch Jaw MI5 or m5 and its complementary switch jaw it or iil'; said switch jaws being mounted as previously described in spaced apart relationship in the channels Qil and @il oi' the base block unit 25.

in order that the switch unit just described may be used as a single pole switch as well as a triple or double pole switch, the switch bar lli is so constructed that the two end portions thereof carrying the two outer switch contact members lll may be brolzen on from the centrai portion leaving the latter with only a single switch contact member. For this purpose, the switch bar iii may be weakened at points inter mediate the switch contact members as by molding into the same moring lines like those indicated at lib.

When using the switch unit as a double pole switch to control the opening and closing of a pair of fused circuits of the character illustrated in the drawings, the elements of the switch, with the exception of pivot pin |64 and switch handle M38, are assembled together in the manner previously described and the unit is inserted through `the"open bottom of the base block unit 25 in the middle channel 93 thereof between partition walls 69 and 90, it being understood that the center knock-out portion of top wall 84 has already been removed so that the free end of arm |86 of the switch lever |65 may project therethrough. In order to properly position the switch unit, the adjacent surfaces oi partition walls 89 and 90 are provided with grooves |19 of suitable width and depth to receive switch` bearing members |56. said grooves extending from top wall 84 to the lowermost portions of semicircular extensions 0|. When the switch unit has thus been placed in channel 98 with the switch bearing members in grooves |19, the pivot pin I 64 is passed through the aligned openings .|63 of bearing members |56 and the eye |61 of the switch bar |65 by inserting the pin through one or the other of a pair of slots |80 formed in the top edges of side walls .82 of the base block unit 25, partition walls 89 and 90 also having openings 8| therein in line with slots |80 to receive said pin. As shown best in Fig. 10, the pivot pin |64 is only slightly shorter than the width of the base block unit and, when in its ilnally assembled position, lies withits extremities in slots |80. The switch handle |66 may then be slid over the outer end of arm |66 of switch lever |65 and the switch is ready for use.

The shape of switch lever |65 and the location of its pivot relative to the pivot of switch arm |58 are such that movement of the switch lever about its pivot moves the switch arm with a snap action in both directions. As shown in Fig. 6, the end of arm |69 of switch lever |65 to which the spring |10 is connected is, in spite of the off-set L-shape of said lever, in line with pivot pin |66 and the free end of arm |66. With this construction, and with the pivot pin |66 spaced as illustrated from the bearing studs |51 upon which switch arm |58 is pivoted, movement ci switch handle |68 moves the inner end of arm |69 from one side to the other of switch arm |58 so as to reverse the direction of pull of spring |10 on said switch arm relative to its pivotal axis on studs |51. 'I'his results in a snap action of the switch arm in both directions, the L-shape of switch lever |65 and the open frame construction of switch arm |58 making it possible for this movement to take place without interference between these two elements.

If it be desired to use the switch' unit of the present invention as a single pole switch, the two end portions of switch bar |12 and their associated stud members |15 and switch contact members |11 may be broken oi from the central portion and the unit mounted-in one or the other of the outer channels 92 and 94 of base block unit 25 in a manner similar to that just described. To accommodate and properly position the bearing members |56 of the switch when thus installed, the outer surfaces of partition walls 89 and 90are provided with grooves |82 similar. to the grooves |19 previously mentioned, while the inner surfaces of side walls 82 of the base block unit are provided with ribs |83 which serve to establish similar grooves |84. When single pole switches are used, it is obvious that each of the fused branch circuits isindividually controllable. The switch unit is also capable of use as a triple pole switch, although there would be very few instances where this would be required in a panel board of the usual construction since three phase branch circuits are very rarely needed in this type of installation. However, if necessary, the switch unit of the present invention could so function either with a few minor changes in the conductor and switch jaw arrangement disclosed, or in some other environment.

There is thus provide'd by the present invention a new and improved panel board system comprising a number of diierent elements which are so designed as to cooperate with one another in the building up of panel boards of any desired size and circuit arrangement. 'I'he elements of the system are themselves of novel construction and adapted for mass production at relatively low cost so that substantial stocks thereof may be economically carried by distributors and wholesalers throughout the country, thereby making it possible for an electrical contractor to obtain without special order all of the elements necessary to build up a panel board of any desired design. The elements are also of such construction that they may be quickly and easily assembled with a minimum use of tools. Another important feature of the invention resides in the fact that there have been provided fuse units of both the plug and cartridge type which are interchangeable one with the other in panel board sections or branch circuit units also of novel construction.

Although only one specific example of panel board assembly embodying the present invention ings, it will be obvious that the invention is not limited to the particular apparatus shown but is capable of a variety of mechanical embodiments. For instance, the construction of each of the various units of the system specifically disclosed may be varied in minor respects and by substituting equivalent elements for those illustrated, particularly as regards the metallic elements forming the current conducting circuits and the switch mechanism. It will also be clear that certain of the elements of the system illustrated, although particularly well adapted for use in combination with the other elements shown, are nevertheless capable of use in other surroundings. Various other changes, which will now become apparent to those skilled in the art, may be made in the form, details of construction and arrangement of the parts without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a deiinition of the limits of the invention.

What is claimed is l. In a panel board assembly, a cabinet, at least one panel board section removably mounted in said cabinet in a horizontally extending position, a pair of bus bars vertically disposed in said cabinet and extending above and below said panel board section, means carried by said panel board section for frictionally engaging and making electrical connection with said bus bars, a terminal block removably mounted in said cabinet above and supported on said panel board section and adapted to support the upper ends of said bus bars, and a block of insulating material for supporting the lower ends of said bus bars, said last named block extending below and having a detachable connection with, said panel board section and being otherwise unconnected to said cabinet.

2. A panel board section of the built-up type comprising a base block unit molded in one piece of non-conducting material and having .side

walls, end walls, an open bottom, a top wall' terminating short of said end walls so as toA and forming the bottoms of said recesses, interchangeable iuse receiving units housed in said the top thereof being complementary to those carried adjacent the bottom thereof whereby a plurality of said body members may be con- Y nected together to form a panel board cabinet of any desired size. f y

8. A base block unit for panel board systems molded in one piece of non-conducting material and comprising a pair of side wallsy extending the entire length of the unit, a pair of end walls connecting said side walls, a top wall connecting said side walls but of less extent lengthwise ,of said unit than said side walls, said top wall terminating a substantial distance short of each of said end walls and leaving a pair of openings of equal size in the top of said unit adjacent the ends thereof, a supporting platform beneath each of said openings extending between said 9. A base block unit -for panel board systems moldedin one piece of non-conducting material and comprising a pair of side walls extending the entire length of the unit, a pair of end walls connecting said side walls, a top wall connecting said side walls but of less extent lengthwise of said unit than said side walls, said top wall terminating a substantial distance short of each of said end walls and leaving a pair of openings of equal size in the top of said unit adjacent the ends thereof, a supporting platform beneath each of said openings extending between said side walls and positioned in a plane intermediate the planes ofthe top wall and bottom edges of the side walls, at least one partition wall extending lengthwise of said unit between said platforms, the bottom of said unit being open and theinterior thereof being divided by said platforms and partition wall or walls into spaces in which fuse receiving and switch elements are adapted to be removably housed, and a plurality of knock-out portions formed in said top wall adapted to provide openings through which the switch operating elements may extend.

10. A base block unit for panel board systems molded in one piece of non-conducting material and comprising a pair of side walls extending the entire length of the unit, a pair of end walls connecting said side walls, a top Ywall connecting said side walls but of less extent lengthwise of said unit than said side Walls, said top wall terminating a substantial distance short of each of said end walls and leaving a pair of openings of equal size in the top of said unit adjacent the ends thereof, a supporting platform beneath each of said openings extending between said side walls and positioned in a plane intermediate the planes of the top wall and bottom edges of the side walls, and at least one partition wall extending lengthwise of said unit between said platforms, said partition wall or walls also being connected to said top wall but of less height than said side walls; the bottom of said unit being open and the interior thereof. being divided by said platforms and partition wall or walls into spaces in which fuse receiving and switch elements are adapted to be removably housed.

11. A base block unit for panel board systems molded in one piece of non-conducting material and comprising a pair of side walls extending the entire length of the unit, a pair of 'end walls connecting said side walls, a ledge projecting outwardly from the bottom portion of each of said end walls, a top wall connecting said side walls but of less extent lengthwise of said unit than said side walls, said top wall terminating a substantial distance short of each of said end walls and leaving a pair of openings of equal size in the top of said unit adjacent the ends thereof, a supporting platform beneath each of said openings extending between said side walls and positioned in a plane intermediate the planes of the top wall and bottom edges of the side walls, and at least one partition wall extending lengthwise of said unit between said platforms, the bottom of said unit being open and the interior thereof being divided by said platforms and partition wall or walls into spaces in which fuse receiving and switch elements are adapted to be removably housed.

12. A base block unit for panel board-systems molded in one piece of non-conducting material Vand comprising a pair of side walls extending the entire length of the unit, a pair of end walls connecting said side walls, a top wall connecting said side walls but of less extent lengthwise of said unit than said side walls, said top wall terminating a substantial distance short of each of said end walls and leaving a pair of openings of equal size in the top of said unit adjacent the ends thereof, a supporting platform beneath each of said openings extending between said side walls and positioned in a plane intermediate the planes of the top wall and bottom edges of the side walls, a pair of parallel partition walls extending lengthwise of said unit between said platforms,v said partition walls being connected to said top wall but of less height than said side walls, the bottom of said unit being open and the interior thereof being divided by said platforms and partition Walls into spaces in which fuse receiving and switch elements are adapted l to be removably housed, vertical grooves formed Areceive certain of said switch elements, and a plurality of knock-out portions formed in said top wall in the same transverse planes as said vertical grooves and overlying the spaces between said side walls and partition walls, saidknockout portions being adapted to provide openings in the top of the unit through which the switch operating elements may extend.

13. A fuse receiving unit for use in a panel board section of the built-up type comprising a base block,a pair of cartridge fuse clips removably mounted on said base block, a cover for said block including a fuse carrier secured to the under side thereof and adapted to receive a cartridge fuse, a pintle member carried by said cover adjacent one edge thereof, a bearing for said pintle member formed in said base block, and a hinge-forming member adapted to engage said pintle member and retain the same in said bearing when said fuse receiving unit is assembled.

14. A fuse receiving unit for use in a panel board section of the built-up type comprising a 'base block, a pair of cartridge fuse clips removably mounted on said base block, a cover for said block including 4a fuse carrier secured to the under side thereof and adapted to -receive a cartridge fuse, an abutment member also se- -fuse is properly positioned with respect to said fuse clips when it is in engagement with said abutment member, a pintle member carried by said cover adjacent one edge thereof, a bearing for said pintle member formed in said base block, and a hinge-forming member adapted to engage said pintle member and retain the same insaid bearing when said fuse receiving unit is assembled. l

15. A fuse receiving unit for use in a panel board section of the built-up type comprising a base block, a pair of cartridge fuse clips removably mounted on said base block, a cover for said block including a fuse carrier secured to the under side thereof and adapted to receive a cartridge fuse, a pintle member carried by said cover adjacent one edge thereof, a bearing for the under surface of said pintle member formed in said base block, and a hinge-forming member having a hook-like portion adapted to engage the upper surface of said pintle member to complete the bearing therefor and another portion adapted to engage the under surface oi said base block Vandrnaintain `thelatter and said cover in hinged vrelationship when said fuse receiving unit is assembled.

16. In a panel board section of the built-up type, a base block unit having a recess formed in the top thereof adjacent one of its ends, said recess being bounded on one side .by the end wall of said unit and on the bottom by a supporting platform, and a fuse receiving unit adapted to be removably housed in said recess comprising a base block adapted to be supported on saidplatforrn', a pair of cartridge fuse clips removably mounted on said base block, a cover for said base bloeit including a fuse carrier secured to the under side thereof and aidapted to receive a cartridge fuse, a pintle member carried by said cover adjacent the edge thereof lying parallel with and nearest to the .end viali of said hase block unit, a bearing for the' under surface oi' said pintle member formed in said base block, and a hingeforming member having a hoch-hire upper end adapted to engage the upper surface of said pintle member to complete the bearing therefor and an inwardly extending projection formed on its lower end adapted to engage the under surface of said base block and lock the elements of the fuse receiving unit in hinged .relationship when said unit is assembled, movement of said projection out ci' locking engagement with said block being preventedby contact between the intermediate portioriof said hinge-for member and the inner surface of the end wali' of said base block unit.

17. A s'witch'unit for use in a panel board section of the built-up type comprising a pair of parallel bearing members, a switch arm pivotaliy mounted on and between smd bearing members at a point intermediate its ends, a pivot pin supported by and extending lbetween. said bearing members, 'a substantially E shaped switch lever mounted on said pivot pin at a point intermediate the ends of one of its arms, a spg connecting fthe free end of the other arm of said level'` and one end of said switch arm, a switch bar mounted on the other end of said switch arm and extending transversely thereto, and a plurality of switch contact members mounted on said switch bar.

18. A switch unit for use in apanel board section `of the `built-up type comprising a pair of parallel bearing membershaving aligned bearing studs projecting inwardly therefrom, a switch arm pivotally mounted on said bearing studs at a point intermediate its ends, a pivot pin extending between said bearing members and passing through aligned openings formed therein, a substantially L-shaped lever having an eye formed at a point intermediate the ends of one of lits arms through which said pivot pin passes, a spring detachably connected to the free end of the other arm of said lever and to one end of said switch arm, "a switch bar removably mounted on the other end of said switch arm and extending transversely thereto, and a plurality of switch l contact members removably mounted on said switch bar. i

19. A switch unit for use in a panel board section of the built-up type comprising a pair of parallel bearing members, a switch arm pivotally mounted on and between said bearing members at a point intermediate its ends, a pivot' pin `supported by and extending between said bearing members, a substantially L-shaped switch lever mounted on said pivot pin at a point inter-- mediate the ends ofone of its arms, a spring connecting the free end of the other arm of said i lever and one end of said switch arm, a switch bar mounted on the other end of said switch arm and extending transversely thereto on both sides thereof, and a plurality of switch contact members mounted on said switch bar at spaced inn tervals therealong, the material of said switch bar being weakened at points intermediate said switch contact members to permit ready removal oi one'or more portions of said bar and the associated contact members.

2h. i panel board section of the built-up type' comprising a base block unit molded in one piece o non-conducting material and having 'side walls, end walls, an open bottom, a 'topv wall wherein there are formed a plurality of fuse receiving recesses of substantial size adjacent the unit ends and supporting platforms positioned in a plane intermediate the planes of the top wall and bottom of the unit and forming the bottoms of said recesses, fuse receiving units removably housed in said recesses andv supported on said platforms, bus bar clipsremovablyl secured to the under sides of said platforms in insulated reiation with respect to said fuse receiving units,

` switch jaw members in electrical connection with said fuse receiving units, complementary switch jaw members in electrical connectiomith said bus bar clips, and switch means removably mounted in the central portion of said base block unit beneath said top vfalliorA opening and closing the circuits acro'ss said switch jaw and complementary switch jawv members.

i l e. 'MCWHORTER 

